Memory device page buffer configuration and methods

ABSTRACT

Memory devices and methods are described that include communication circuitry between page buffers in a memory array. Examples include communication circuitry that provide status information of page buffers that are directly adjacent to a given page buffer. The exchanged information can be used to adjust a given page buffer to compensate for effects in directly adjacent data lines that are being operated at the same time.

PRIORITY APPLICATION

This application is a continuation of U.S. application Ser. No.12/612,248, filed Nov. 4, 2009, now issued as U.S. Pat. No. 8,243,529,which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

Various embodiments described herein relate to apparatus, systems, andmethods associated with semiconductor memories.

BACKGROUND

In semiconductor memories, there is continuous pressure in industry toreduce component dimensions and fit more components in a given amount ofchip area. As dimensions shrink, numerous technical hurdles become moresignificant. For example in non-volatile memory devices, such as NANDmemory, when data line spacing is reduced, adjacent data lines begin toaffect each other during operation. One solution to this problem hasbeen to only operate every other data line at one time. This approachsimply ignores the effect of adjacent data lines by never operatingadjacent data lines at the same time. Improved memory deviceconfigurations and methods are desired to provide improved deviceoperation and ability to operate at smaller scales.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a block diagram of a memory device according to anembodiment of the invention.

FIG. 2 shows a method of operating a memory device according to anembodiment of the invention.

FIG. 3 shows an information handling system, including a memory deviceaccording to an embodiment of the invention.

DETAILED DESCRIPTION

In the following detailed description of the invention, reference ismade to the accompanying drawings that form a part hereof and in whichare shown, by way of illustration, specific embodiments in which theinvention may be practiced. These embodiments are described insufficient detail to enable those skilled in the art to practice theinvention. Other embodiments may be utilized and structural, logical,and electrical changes may be made.

FIG. 1 shows selected portions of a memory device 100 according to anembodiment of the invention. The memory device includes an array 150 ofmemory cells. An example memory cell 118 is shown within the array 150.Types of memory cells 118 in the array 150 include flash memory cells inany suitable logical configuration, such as NAND, NOR, etc. In FIG. 1,an access line such as a word line 113, and a sourceline 116 are showncoupled to a row of memory cells 118. Although flash memory cells areused as an example, arrays with other types of memory cells can be usedwith embodiments of the invention.

A number of data lines, such as data lines 112, are shown leading intothe array 150. In the example shown, each data line 112 is coupled to apage buffer 110. The page buffers 110 control the programming andreading activity of each data line 112. In one example, each page buffer110 includes a logic block 120 that is used to control functions of thepage buffer 110. Functions controlled by the logic blocks 120 include,but are not limited to data line voltage during a read operation; dataline voltage during a program operation; an amount of time at a givendata line voltage during various operations; etc. Although FIG. 1illustrates an individual logic block 120 in each page buffer 110 tocontrol each page buffer 110 and its corresponding data line status,other configurations are also within the scope of the invention. Forexample, more than one page buffer 110 may share a given logic block120. In one example, the logic block 120 is implemented through amodule. A module can be hardware, software, firmware, or combinations ofthe above.

FIG. 1 further illustrates an embodiment including communicationcircuitry 114 between the page buffers 110. Information about a statusof a variable of each page buffer 110 can be passed from page buffer topage buffer using the communication circuitry 114. In one embodiment,each page buffer 110 is provided with information regarding a variableof one or more directly adjacent page buffers 110 using thecommunication circuitry 114. A status of each page buffer indicates astatus of its corresponding data line 112. Possible variables include,but are not limited to, voltage levels, programmed state, time remainingin a current operation, etc. As discussed above, any of several dataline variables and their status can affect operation and/or performanceof directly adjacent data lines.

In one embodiment, the communication circuitry 114 is passive. Theconnections provide information at all times during device operation,and the information is used as needed. In other embodiments, thecommunication circuitry 114 is active. In an active configuration, thecommunication circuitry 114 is only activated when queried by forexample an adjacent page buffer 110. Examples of implementation forcommunication circuitry include, but are not limited to, metal tracewiring, or other conductive traces, transistors or other switches,and/or other electrical signal pathways.

In one embodiment, because the communication circuitry 114 makes pagebuffer status and resulting data line status available to adjacent pagebuffers, the status in a given data line 112 can be compensated for inan adjacent data line 112. In one embodiment, a given page buffer 110knows its own status (programming, reading, voltage setting, timescheduled for a give operation, etc.) and a status of its correspondingdata line 112. The given page buffer 110 also checks a status of one ormore directly adjacent page buffers 110 that correspond to theirrespective data lines 112. Then, the given page buffer 110 can make anadjustment to its own status, if necessary, to compensate for the statusof the one or more adjacent page buffers 110. In this way, memory deviceconfigurations as discussed and illustrated can operate adjacent datalines at the same time without an unacceptable number of errors, or lossof performance.

FIG. 2 shows a flow diagram of an example method according to anembodiment of the invention, having selected similar attributes toconfigurations described above. In operation 202, a first variable iscontrolled on a first data line using a first page buffer. In operation204, a second variable on a second data line directly adjacent to thefirst data line is controlled using a second page buffer.

In operation 206, information is exchanged between the first page bufferand the second page buffer. As discussed above, examples of informationthat can be exchanged includes, but is not limited to, data linevoltages, types of operations being performed such as programming,reading, etc., length of time at a given voltage, etc. Other examples ofinformation that can be exchanged includes an operational state of thepage buffer, such as “currently programming” or “currently reading,”“holding,” etc.

In one embodiment, “holding” is used to describe a voltage put onto adata line to maintain the states of memory cells on the data line. Thepresence of a holding voltage provides a voltage barrier to ensure thata charge on a floating gate does not leak out and compromiseperformance.

In selected embodiments, different operations are compensated fordifferently, therefore information about an operational state can beused to respond to each of the different operations.

In operation 208, the second variable (for example voltage) on thesecond data line is adjusted to compensate for effects from the firstvariable (for example, voltage) on the directly adjacent first dataline. In one example, a second voltage is raised to compensate foreffects from the a voltage on the directly adjacent first data line. Inone example, the second voltage is lowered to compensate for effectsfrom the first voltage on the directly adjacent first data line.Although adjusting voltages as a method of compensation is used as anexample, various embodiments of the invention are not so limited. Othervariables such as programming time, reading time, etc. can also beadjusted to compensate for effects from adjacent data lines.

One challenge with operating directly adjacent data lines at the sametime includes programming time being affected by directly adjacent datalines causing programming to occur too quickly. Such an issue ofprogramming occurring too quickly is more important in selected memorydevices, such as multistate memory devices. One example of multistatememory devices programs a gate of a memory cell with a plurality ofthreshold voltages to form the multiple memory states. In one examplememory device according to an embodiment of the invention, any of anumber of possible techniques to compensate and slow down a programmingrate are utilized. As discussed above, examples include, but are notlimited to, varying data line voltages and changing time allotted for agiven operation such as programming or reading.

An embodiment of an information handling system such as a computer isincluded in FIG. 3 to show an embodiment of a high-level deviceapplication. FIG. 3 is a block diagram of an information handling system300 incorporating at least one chip or chip assembly 304 that includes amemory device 307 according to an embodiment of the invention. In oneexample, the memory device 307 includes a multistate memory device. Theinformation handling system 300 shown in FIG. 3 is merely one example ofa system in which the present invention can be used. Other examplesinclude, but are not limited to, personal data assistants (PDAs),cellular telephones, MP3 players, aircraft, satellites, militaryvehicles, etc.

In this example, information handling system 300 comprises a dataprocessing system that includes a system bus 302 to couple the variouscomponents of the system. System bus 302 provides communications linksamong the various components of the information handling system 300 andmay be implemented as a single bus, as a combination of busses, or inany other suitable manner.

Chip assembly 304 is coupled to the system bus 302. Chip assembly 304may include any circuit or operably compatible combination of circuits.In one embodiment, chip assembly 304 includes a processor 306 that canbe of any type. As used herein, “processor” means any type ofcomputational circuit such as, but not limited to, a microprocessor, amicrocontroller, a graphics processor, a digital signal processor (DSP),or any other type of processor or processing circuit. Multipleprocessors such as “multi-core” devices are also within the scope of theinvention.

In one embodiment, a memory device 307, such as a memory devicedescribed in embodiments above, is included in the chip assembly 304.Those skilled in the art will recognize that a wide variety of memorydevice configurations may be used in the chip assembly 304. Acceptabletypes of memory chips include, but are not limited to, Dynamic RandomAccess Memory (DRAMs) such as SDRAMs, SLDRAMs, RDRAMs and other DRAMs.Memory chip 307 can also include non-volatile memory such as NAND memoryor NOR memory.

In one embodiment, additional logic chips 308 other than processor chipsare included in the chip assembly 304. An example of a logic chip 308other than a processor includes an analog to digital converter. Othercircuits on logic chips 308 such as custom circuits, anapplication-specific integrated circuit (ASIC), etc. are also includedin one embodiment of the invention.

Information handling system 300 may also include an external memory 311,which in turn can include one or more memory elements suitable to theparticular application, such as one or more hard drives 312, and/or oneor more drives that handle removable media 313 such as floppy diskettes,compact disks (CDs), digital video disks (DVDs), and the like. A memoryconstructed as described in examples above is included in theinformation handling system 300.

Information handling system 300 may also include a display device 309such as a monitor, additional peripheral components 310, such asspeakers, etc. and a keyboard and/or controller 314, which can include amouse, or any other device that permits a system user to inputinformation into and receive information from the information handlingsystem 300.

While a number of embodiments of the invention are described, the abovelists are not intended to be exhaustive. Although specific embodimentshave been illustrated and described herein, it will be appreciated bythose of ordinary skill in the art that any arrangement that iscalculated to achieve the same purpose may be substituted for thespecific embodiment shown. This application is intended to cover anyadaptations or variations of the present invention. It is to beunderstood that the above description is intended to be illustrative andnot restrictive. Combinations of the above embodiments, and otherembodiments, will be apparent to those of skill in the art upon studyingthe above description.

What is claimed is:
 1. An apparatus, comprising: a first data lineassociated with a first plurality of memory cells; a second data linedirectly adjacent to the first data line and coupled to a secondplurality of memory cells; a first page buffer operable to control anactivity of the first data line; a second page buffer operable tocontrol an activity of the second data line; communication circuitrycoupled between the first and second page buffers and operable to passinformation about a voltage associated with the second data line to thefirst page buffer; and further including circuitry to raise a voltage onthe first data line in response to the information about the voltageassociated with the second data line.
 2. The apparatus of claim 1,wherein the first plurality of memory cells and second plurality ofmemory cells include multistate memory cells.
 3. The apparatus of claim1, wherein the communication circuitry is active.
 4. The apparatus ofclaim 1, wherein the communication circuitry is passive.
 5. Theapparatus of claim 1, further including a processor in communicationwith the memory cells.
 6. The apparatus of claim 1, wherein the firstplurality of memory cells and the second plurality of memory cells areeach connected in a NAND configuration.
 7. An apparatus, comprising: afirst data line associated with a first plurality of memory cells; asecond data line directly adjacent to the first data line and coupled toa second plurality of memory cells; a first page buffer operable tocontrol an activity of the first data line; a second page bufferoperable to control an activity of the second data line; and a moduleoperable to adjust a programming time of the memory cells associatedwith the first data line responsive to information about the second dataline.
 8. The apparatus of claim 7, wherein the module operable to adjustthe programming time includes a module operable to adjust a voltage ofthe first data line.
 9. The apparatus of claim 7, wherein the module isoperable to adjust the programming time responsive to an operationalstate of the second data line.
 10. The apparatus of claim 7, wherein themodule is operable to adjust the programming time responsive to a seconddata line operational state from a group consisting of “currentlyprogramming,” “currently reading,” and “holding.”
 11. The apparatus ofclaim 7, wherein the module includes modules located locally in each ofthe first and second page buffers.
 12. A method, comprising: controllinga variable associated with a first data line using a first page buffer;controlling a variable associated with a second data line directlyadjacent to the first data line using a second page buffer; exchanginginformation about the variable associated with the first and second datalines between the first page buffer and the second page buffer; andadjusting a variable associated with the second data line to compensatefor variations in programming speed associated with the second dataline.
 13. The method of claim 12, wherein adjusting a variable includesadjusting a voltage.
 14. The method of claim 12, wherein adjusting avariable includes adjusting a program time.
 15. The method of claim 12,wherein exchanging information includes exchanging voltage information.16. The method of claim 12, wherein exchanging information includesexchanging operational state information.
 17. The method of claim 16,wherein the operational state information is from a group consisting of“currently programming,” “currently reading,” and “holding.”
 18. Anapparatus, comprising: a first data line associated with a firstplurality of memory cells; a second data line directly adjacent to thefirst data line and coupled to a second plurality of memory cells, thefirst and second data lines being located within the same memory array;a first page buffer operable to control an activity of the first dataline; a second page buffer operable to control an activity of the seconddata line; communication circuitry coupled between the first and secondpage buffers and operable to pass information about a voltage associatedwith the second data line to the first page buffer.
 19. An apparatus,comprising: a first data line associated with a first plurality ofmemory cells; a second data line adjacent to the first data line andcoupled to a second plurality of memory cells, the first and second datalines being located within the same memory array and having no otherdata lines located between the first and second data line; a first pagebuffer operable to control an activity of the first data line; a secondpage buffer operable to control an activity of the second data line;communication circuitry coupled between the first and second pagebuffers and operable to pass information about a voltage associated withthe second data line to the first page buffer.